package demo1;

import java.util.Queue;

public class MyLinkedList {
    ListNode head;
    new Queue<String>();
    ListNode last;
    static class ListNode{
        int val;
        ListNode prev;
        ListNode next;

        public ListNode(int val) {
            this.val = val;
        }
    }
    //头插法
    public void addFirst(int data){
        ListNode node = new ListNode(data);
        if(head == null){
            head = node;
            last = node;
        }else{
            head.prev = node;
            node.next = head;
            head = node;
        }
    }
    //尾插法
    public void addLast(int data){
        ListNode node = new ListNode(data);
        if(head == null){
            head = node;
            last = node;
        }else{
            last.next = node;
            node.prev = last;
            last = node;
        }
    }
    //任意位置插入,第一个数据节点为0号下标
    public void addIndex(int index,int data){
        if(index == 0){
            addFirst(data);
            return;
        }
        if(index == size()){
            addLast(data);
            return;
        }
        ListNode node = new ListNode(data);
        ListNode cur = searchIndex(index);
        node.prev = cur.prev;
        node.next = cur;
        cur.prev.next = node;
        cur.prev = node;
    }
    public ListNode searchIndex(int index){
        ListNode cur = head;
        for (int i = 0; i < index; i++) {
            cur = cur.next;
        }
        return cur;
    }
    private void chakedidex(int index){

        if (index < 0 || index > size()){
            throw new IdexOutOf("index 不合法" + index);
        }
    }
    //查找是否包含关键字key是否在单链表当中
    public boolean contains(int key){
        ListNode cur = head;
        while(cur != null){
            if(cur.val == key)return true;
            cur = cur.next;
        }
        return false;
    }
    //删除第一次出现关键字为key的节点
    public void remove(int key){

    }
    //删除所有值为key的节点
    public void removeAllKey(int key){

    }
    //得到单链表的长度
    public int size(){
        ListNode cur = head;
        int ret = 0;
        while(cur != null){
            ret++;
            cur = cur.next;
        }
        return ret;
    }

    public void display(){
        ListNode cur = head;
        while(cur != null){
            System.out.print(cur.val + " ");
            cur = cur.next;
        }
        System.out.println();
    }
    public void clear(){
        ListNode cur = head;
        while(cur != null){
            ListNode curNext = cur.next;
            cur.prev = null;
            cur.next = null;
            cur = curNext;
        }
        head = null;
        last = null;
    }
}
